The reason for their beauty (well, one, possibly)

Trees may get their beautiful shapes from battling the elements. A mathematical model shows that the pattern some branches make, first noted by Leonardo da Vinci, is the best at withstanding gusts of wind.

Da Vinci observed that at any height above the ground, the total cross section of some trees’ branches has roughly the same area as that of the trunk. This pattern was thought to accommodate the tree’s plumbing, as water flows fastest when the branched pipes can hold as much water as the original pipe. But Christophe Eloy at the University of California in San Diego thought trees contained too little plumbing to be the reason behind the pattern.

Instead he thought wind might play a role. So he built a model to simulate the bending forces exerted by the wind, and found that trees with branch thicknesses fitting da Vinci’s rule resisted breakage. The work will appear in Physical Review Letters.

The model could help architects design wind-resistant buildings that mimic tree branches, says plant biophysicist Karl Niklas at Cornell University in Ithaca, New York.